Throttle return spring redundancy system

ABSTRACT

A throttle valve, situated within the induction passage of a fuel or air induction device, is carried by a throttle shaft for rotation therewith; a lever fixedly connected to the throttle shaft is operatively to a remotely situated operator&#39;&#39;s footoperated throttle control; a first throttle return spring is operatively connected to the first lever for returning the throttle valve to an idle position whenever the foot-operated throttle control is released; a second safety spring is provided for assuring the movement of the throttle valve to the idle position in the event that, for example, either the first throttle return spring or the associated throttle control linkage should fail while the throttle valve is in either a partly or fully opened position; the manually operated throttle control being effective to force opening movement of the throttle valve against the resilient resistance of the second safety spring.

Eshelman 1 Oct. 24, 1972 [54] THROTTLE RETURN SPRING REDUNDANCY SYSTEMPhilip V. Eshelman, 19417 Greenwald Drive, Southfield, Mich. 48075 22]Filed: June 7,1971

21] Appl.No.: 150,670

[72] Inventor:

[56] References Cited UNITED STATES PATENTS 3,626,919 12/1971 MacMillan..l23/ 198 DB Primary Examiner-Wendell E. Burns Att0rneyWalter Potoroka,Sr.

[57] ABSTRACT A throttle valve, situated within the induction passage ofa fuel or air induction device, is carried by a throttle shaft forrotation therewith; a lever fixedly connected to the throttle shaft isoperatively to a remotely situated operators foot-operated throttlecontrol; a first throttle return spring is operatively connected to thefirst lever for returning the throttle valve to an' idle positionwhenever the foot-operated throttle control is released; a second safetyspring is provided for assuring the movement of the throttle valve tothe idle position in the event that, for example, either the firstthrottle return spring or the associated throttle control linkage shouldfail while the throttle valve is in either a partly or fully openedposition; the manually operated throttle control being effective toforce opening movement of the throttle valve against the resilientresistance of the second safety spring.

7 Claims, 4 Drawing Figures PATENTEUUET 24 I972 3,699,943

- sum 1 UF 2 N R. 5 (33%; VAZQZZH M W (5.

ATTORNEY PATENTEDH 2 m2 3 999,943

SHEU 2 OF 2 N N I ll? 2 50 I .u 34 a 52 I 50 8 INVENTOR.

ATTORNEY BACKGROUND OF THE INVENTION Heretofore, carburetors or otherengine induction devices employing an induction passage with a throttlevalve therein, had a lever fixed to the throttle shaft which lever, inturn, was operatively connected to associated throttle control linkage(as the vehicle operators foot-controlled throttle pedal within thevehicle passenger compartment) and to a return spring for returning thethrottle valve to an engine idle position when control over the throttlehad been relinquished by the vehicle operator.

Even though such carburetors and induction devices have performed wellin the past and have not shown any tendency to experience failure ofsuch a throttle return spring or the associated throttle controllinkage, the Federal Government has, nevertheless, recently issued newproposed safety standards in regard to driveroperated throttle oraccelerator control systems.

Such standards, among other things, require that: (l) in the event thenormal or usual throttle return spring should fail, means must beprovided for assuring that the throttle valve will return to its idleposition; (2) in the event the associated throttle control linkageshould fail, means must be provided for assuring that the throttle valvewill return to its idle position; and (3) the vehicle operator muststill be able to exercise a degree of control over the position of thethrottle valve with the occurrence of the events set forth in (1) and(2),

above.

Accordingly, the invention as herein disclosed is primarily concernedwith the solution of the above as well as other related problems.

SUMMARY OF THE INVENTION According to the invention, an automaticthrottle return device comprises a first lever adapted for connection toan associated throttle shaft and throttle valve for rotation therewith,first spring means for rotating said first lever and throttle valve toan idle position during normal operating conditions, second safetyspring means energized upon failure of said first spring means forassuring rotation of said first lever and said throttle valve to saididle position, and manually actuated lever means effective for causingopening movement of the throttle valve against the resistance of thesecond safety spring means upon failure of the first spring means.

DESCRIPTION OF THE DRAWINGS In the drawings wherein, for purposes ofclarity, certain details and elements may be omitted from one or moreviews:

FIG. 1 is a fragmentary elevational view of a carburetor or otherinduction device equipped with a throttle control embodying theinvention;

FIG. 2 is a view similar to FIG. 1 with certain elements shown in FIG. 1removed for purposes of clarity and showing remaining elements inpositions corresponding to normal operation;

FIG. 3 is a view similar to FIG. 2 but illustrating the elements inpositions assumed resulting from a failure of the normal throttle returnspring; and

I FIG. 4 is a cross-sectional view taken generally on the plane of line4-4 of FIG. 1 and looking in the direction of the arrows.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now in greater detailto the drawings, FIG. 1 illustrates a fragmentary portion of acarburetor 10 having an induction passage 12 formed therethrough with ajournalled throttle shaft 14 extending transversely through theinduction passage or bore 12. A throttle valve 16, situated within theinduction passage 12, is suitably fixedly secured to and carried bythrottle shaft 14 for rotation therewith within the induction passagefor controlling flow therethrough to the related engine 18.

The throttle return device 20, referring in particular to FIG. 1 and 4,is shown as being comprised of a first lever 22 having a mountingaperture 24 by which it is mounted onto throttle shaft 14 and securedthereto for rotation therewith as by keying fiatted portions 26 formedon the shaft 14 and cooperating flatted portions 28 formed in theaperture 24 of lever 22. A pivot pin 30, which may be pressed into anaperture 32 of lever 22 as to be secured thereto, pivotally supports alatching lever 34 which, in turn, as shown in FIGS. 1, 2 and 3, has itsother end operatively connected to a throttle return tension spring 36having its opposite end suitably anchored as at 38.

A second latching or throttle control lever 40 is preferably fixedlysecured to a bushing 42 which, in turn, is freely received on anecked-down portion 44 of throttle shaft 14 so as to be rotatable withrespect thereto. A drum-like member 46 is also freely journalled on thereduced diameter 44 of shaft 14 and axially retained thereon as by awasher or thrust bearing 48 and a C-clip 50. The drum 46 serves togenerally carry and retain a coiled torsion safety spring 52 thereabout.

As shown in FIGS. 1, 2 and 3, levers 22 and 40 are respectively providedwith generally laterally extending arm portions .54 and 56 to which areoperatively connected hooked ends 58 and 60 of torsion spring 52 so asto result in lever 22 being urged counter-clockwise and lever 40 beingurged clockwise.

Another arm portion 62 of lever 22 is pivotally connected to one end 64of a motion transmitting member such as a rod 66 which, in turn, isoperatively connected as to the foot operated throttle control lever orpedal 68 within the vehicle engine compartment.

As best seen in FIG. 4, the main body portions of levers 34 and 40 aresubstantially in the same plane. This is done to enable such levers tocoact with each other as by having a tongue-like latching projection 70,formed on lever 34, received within a cooperating recess or slot 72formed in lever 40.

For the moment neglecting the latching projection 70 and recess 72, itcan be seen that the only lever which is in any way fixed or secured fordriving rotation of the throttle valve 16 is lever 22 because lever 40is rotatable with respect to throttle shaft 14 and lever 34 is pivotallycarried by lever 22.

OPERATION OF THE INVENTION For purposes of description, let it be firstassumed that the elements are in the respective positions as shown inFIGS. 1 and 2. At this time the throttle valve 16 will be in thenominally closed or idle position within induction passage 14 asgenerally depicted in, for example, FIG. 1. Also, as illustrated in FIG.2, the torsion safety spring 52 is urging the levers 22 and 40 in thedirections previously described but is precluded from so moving thelevers because of projection 70 being engaged within latching recess 72.This engagement between member 70 and latching recess 72 is maintainedby the spring 36 which also serves to provide the force for returningthe throttle shaft 14 and throttle valve 16 to the idle position.

During normal operation when opening movement of the throttle valve 16is desired, foot-operated throttle pedal 68 is rotated clockwise aboutits pivot support 74 causing rod or linkage means 66 to move to theright causing clockwise rotation of lever 22 which, because of it beingfixedly or drivingly secured to shaft 14, causes clockwise rotation ofthrottle shaft 14 with throttle valve 16 thereby being rotated in theopening direction. Levers 34 and 40, being held in latched engagement toeach other through the resilient effect of return spring 36, are alsorotated clockwise through motion transmitted from lever 22 to latchinglever 34 via pivot connection 30.

When throttle control pedal 68 is released, the return spring 36 pullsat the lower end of lever 34 causing counter-clockwise rotation oflevers 40 and 22. This, in turn, results in throttle shaft 14 also beingturned counter-clockwise with throttle valve 16 being returned to idleposition.

Further, as is generally well known in the art, a suitable throttle stopscrew 80 may be provided as generally depicted in FIG. 3. The screw 80may be threadably carried by an arm portion 82 of a lever-like member 84suitably fixedly secured to the throttle shaft 14 so as to rotatetherewith. The purpose of such a stop screw is, of course, to coact witha suitable abutment 86 and in so doing determine the idle position ofthe throttle valve 16.

Let it now be assumed that throttle rod or linkage 66 has causedclockwise rotation of levers 40, 34 and 22 to a position where, forexample, the throttle valve 16 is approaching a wide open position.Further, let it be assumed that at that moment the throttle returnspring 36 breaks or in some way fails. If this were to happen, the forcepreviously exerted by spring 36, holding detent or latching lever 34 inlatched engagement with lever 40, would be eliminated causing levers 40and 34 to become disengaged from each other. That is, referring to FIGS.2 and 3, it can be seen that in the preferred embodiment of theinvention, the sides of the notch or slot 72 are made slightly taperedas are the juxtaposed sides of the latching projection 70. Consequently,the torsional force of torsion spring 52 continually urges theprojection 70 out of seated engagement with the slot or recess 72.However, in normal operation return spring 36 provides enough force toprevent disengagement between latching portions 70 and 72. Therefore, ifreturn spring 36 should fail, the force of torsion spring 52 forces thelatch tongue 70 out of engagement with latch slot 72.

With the latching means thusly disengaged, torsion spring 52, throughits end 60 engaged with arm 56 of lever 40, causes lever 40 to rotateclockwise until a transverse arm portion 88 of lever 40 strikes andabuts against an abutment portion 90 which may be a fixed abutmentcarried by the carburetor 10 to determine the maximum throttle openingof throttle 16. Once lever 40 is thusly brought to rest against abutment90, the torsion spring through its end 58 engaged with arm 54 of lever22 continues to urge lever 22 and throttle shaft 14 in acounter-clockwise direction or towards a closed (idle) throttle positionof FIG. 1 as determined, for example, by the idle stop screw of FIG. 3.

It should be remembered that lever 22 is fixed to throttle shaft 14 sothat rotation of one causes rotation of the other. Therefore, it will beobserved that when return spring 36 has failed torsion spring 52 willreturn the throttle valve 16 to its idle position whenever control overthe throttle valve 16 is relinquished by the operator as by releasingthe throttle pedal or lever 68 of FIG. 1.

In view of the above, it can be seen that if the normal throttle return36 should fail the safety torsion spring 52 automatically assumes thefunction of providing a resilient force urging the throttle valve 16towards a closed or idle position while still permitting the operator tocontinue exercising control over the opening of the throttle valve.However, the invention as herein disclosed contemplates an additionalbenefit. That is, the safety spring 52 is preferably selected as to havea spring rate and preload force of such magnitude as to thereby exhibita decidedly increased resistance toward opening movement of the throttlevalve 16 as compared to the resistance offered by the normal throttlereturn spring 36.

For example, the safety spring 52 may be of such a spring rate andpreload force as to, when actuated and released in the manner describedabove, require twice as much effort on the part of the vehicle operatorto move the throttle valve 16 in the opening direction as compared tothe resilient resistive force of the normal throttle return spring.Therefore, whenever, the normal return spring 36 fails and the safetyspring 52 assumes the function of being a throttle return spring, thevehicle operator is immediately placed on notice, by virtue of theincreased effort required of him, that something has gone wrong with histhrottle control system and will therefore seek the assistance ofqualified personnel for inspection and corrective maintenance of thevehicle.

Although only one preferred embodiment of the invention has beendisclosed and described it should be apparent that other embodiments andmodifications of the invention are possible within the scope of theappended claims.

I claim:

1. Apparatus for assuring the return of a throttle valve from a partlyopened or fully opened position to an idle position, comprising a shaftrotatable in accordance with the rotation of said throttle valve, firstmanually actuated throttle control linkage means operatively connectedto said shaft for at times causing rotation of said shaft and saidthrottle valve in a throttle opening direction, first spring meansreacting against a first abutment and operatively connected to saidshaft and throttle valve for applying a first resilient forcethereagainst in a direction opposite to said throttle opening directionin order to at times rotate said shaft and said throttle valve to saididle position, and second resilient means effective upon the occurrenceof a failure in said first spring means to automatically react against asecond abutment for urging said shaft and throttle valve to be rotatedin a direction toward said idle position.

2. Apparatus according to claim 1, including latching means normallyeffective for preventing said second resilient means from reactingagainst said second abutment, said latching means becoming disengagedand ineffective for preventing said second resilient means from reactingagainst said second abutment when said first spring means experiences afailure.

3. Apparatus according to claim 1, wherein said second resilient meanshas a substantially greater preload force than said first spring meansand a substantially lesser spring rate than said first spring means.

4. Apparatus according to claim 1, where in said first manually actuatedthrottle control linkage means comprises a first lever connected to saidshaft for driving rotation therewith, including a second lever freelyjournalled with respect to said shaft, wherein said second resilientmeans is operatively connected to said first lever and said second leverso as continually urge said second lever to rotate with respect to saidfirst lever and said shaft, detent means for normally preventing saidsecond lever from rotating with respect to said first lever, whereinsaid first spring means is effective for maintaining said detent meansengaged thereby preventing said second lever from rotating with respectto said first lever, said detent means becoming disengaged upon failureof said first spring means thereby permitting said second resilientmeans to rotate said second lever against said second abutment andthereby react to resiliently urge said first lever said shaft and saidthrottle valve toward said idle position.

5. Apparatus according to claim 4, wherein said second resilient meanscomprises a coiled torsion spring having first and second arm portionsrespectively engaging said first lever and said second lever, whereinsaid detent means comprises a third pivotally supported levertranslationally carried by said shaft, a

first detent portion formed on said third lever adapted for operativeengagement with a second detent portion carried by said second lever,and wherein said first spring means normally urges said first and seconddetent portions into engagement with each other.

6. Apparatus according to claim 5, wherein said third lever is pivotallyconnected to said first lever, wherein said first detent portioncomprises a tongue-like projection, and wherein said second detentportion comprises a generally radially directed slot formed in saidsecond lever for receiving said tongue-like projection.

7. Apparatus according to claim 6, wherein said tongue-like projectionhas a first cam-like surface, wherein said radially directed slot has asecond cam-like surface, said first and second cam-like surfaces beingjuxtaposed and engaged whenever said tongue-like projection is receivedand retained in said slot, and wherein said coiled torsion springthrough its continued urging or rotation of said second lever causessaid second cam-like surface to urge said first cam-like surface andsaid tongue-like proj ecti on utpf sgid slot.

1. Apparatus for assuring the return of a throttle valve from a partlyopened or fully opened position to an idle position, comprising a shaftrotatable in accordance with the rotation of said throttle valve, firstmanually actuated throttle control linkage means operatively connectedto said shaft for at times causing rotation of said shaft and saidthrottle valve in a throttle opening direction, first spring meansreacting against a first abutment and operatively connected to saidshaft and throttle valve for applying a first resilient forcethereagainst in a direction opposite to said throttle opening directionin order to at times rotate said shaft and said throttle valve to saididle position, and second resilient means effective upon the occurrenceof a failure in said first spring means to automatically react against asecond abutment for urging said shaft and throttle valve to be rotatedin a direction toward said idle position.
 2. Apparatus according toclaim 1, including latching means normally effective for preventing saidsecond resilient means from reacting against said second abutment, saidlatching means becoming disengaged and ineffective for preventing saidsecond resilient means from reacting against said second abutment whensaid first spring means experiences a failure.
 3. Apparatus according toclaim 1, wherein said second resilient means has a substantially greaterpreload force than said first spring means and a substantially lesserspring rate than said first spring means.
 4. Apparatus according toclaim 1, where in said first manually actuated throttle control linkagemeans comprises a first lever connected to said shaft for drivingrotation therewith, including a second lever freely journalled withrespect to said shaft, wherein said second resilient means isoperatively connected to said first lever and said second lever so ascontinually urge said second lever to rotate with respect to said firstlever and said shaft, detent means for normally preventing said secondlever from rotating with respect to said first lever, wherein said firstspring means is effective for maintaining said detent means engagedthereby preventing said second lever from rotating with respect to saidfirst lever, said detent means becoming disengaged upon failure of saidfirst spring means thereby peRmitting said second resilient means torotate said second lever against said second abutment and thereby reactto resiliently urge said first lever said shaft and said throttle valvetoward said idle position.
 5. Apparatus according to claim 4, whereinsaid second resilient means comprises a coiled torsion spring havingfirst and second arm portions respectively engaging said first lever andsaid second lever, wherein said detent means comprises a third pivotallysupported lever translationally carried by said shaft, a first detentportion formed on said third lever adapted for operative engagement witha second detent portion carried by said second lever, and wherein saidfirst spring means normally urges said first and second detent portionsinto engagement with each other.
 6. Apparatus according to claim 5,wherein said third lever is pivotally connected to said first lever,wherein said first detent portion comprises a tongue-like projection,and wherein said second detent portion comprises a generally radiallydirected slot formed in said second lever for receiving said tongue-likeprojection.
 7. Apparatus according to claim 6, wherein said tongue-likeprojection has a first cam-like surface, wherein said radially directedslot has a second cam-like surface, said first and second cam-likesurfaces being juxtaposed and engaged whenever said tongue-likeprojection is received and retained in said slot, and wherein saidcoiled torsion spring through its continued urging or rotation of saidsecond lever causes said second cam-like surface to urge said firstcam-like surface and said tongue-like projection out of said slot.